Cleaning the coils and fan blades is a once a year job for me. Unplug the fridge, use one of those coil cleaning brushes you can buy at any big box store while having a good vacuum cleaner hose to suck out what you brush off of the coils and fan blades. Most motors will be permantely lubricated so don't worry about that. IF, and most likely, you have a condensate drain pan, remove it for a really good cleaning. All that crappy moisture that goes in there brings in weird solids that harden when the pan is dried out and harbors all sorts of bacteria. Good Luck, David